INHBB
Inhibin, beta B, also known as INHBB, is a protein which in humans is encoded by the INHBB gene.[5][6] INHBB is a subunit of both activin and inhibin, two closely related glycoproteins with opposing biological effects.
Function
Inhibin
Inhibins are heterodimeric glycoproteins composed of an α subunit (INHA) and one of two homologous, but distinct, β subunits (βA or βB, this protein). mRNA for the two subunits has been demonstrated in the testes of adult rats.[7] Inhibin can bind specifically to testicular interstitial cells throughout development and may be an important regulator of Leydig cell testosterone production or interstitial cell function.[8]
The inhibin beta B subunit joins the α subunit to form a pituitary FSH secretion inhibitor. Inhibin has been shown to regulate gonadal stromal cell proliferation negatively and to have tumour-suppressor activity. In addition, serum levels of inhibin have been shown to reflect the size of granulosa-cell tumors and can therefore be used as a marker for primary as well as recurrent disease. Because expression in gonadal and various extragonadal tissues may vary severalfold in a tissue-specific fashion, it is proposed that inhibin may be both a growth/differentiation factor and a hormone.
Activin
Furthermore, the beta B subunit forms a homodimer, activin B, and also joins with the beta A subunit to form a heterodimer, activin AB, both of which stimulate FSH secretion.[6]
Tissue distribution
Sections of testicular tissue from rat revealed positive immunoreactivity against anti-inhibin intensely appeared in Leydig cells.[9] In adult animals, binding of 125I inhibin was localized primarily to the interstitial compartment of the testis.[8] Also, Jin et al., (2001) reported that Leydig cells showed strong positive staining for the inhibin βA subunit in pigs testis.[10]
Receptors
In situ ligand binding studies have shown that 125I inhibin βA binds specifically to Leydig cells throughout rat testis development. These results suggest that inhibin has been considered as a regulator of Leydig cell differentiated function.[11][12] Recently, additional inhibin specific binding proteins were identified in inhibin target tissues, including pituitary and Leydig cells.[13][14] From these receptors β-glycan (the TGFß type III receptor) and InhBP/p120 (a membrane-tethered proteoglycan) were identified as putative inhibin receptors and they are all present in Leydig cells. However, a faint positive reaction was detected in Leydig cell cytoplasm in rats treated with anise oil.[9] This may be related to the damaged Leydig cells, as a result of the decreasing of inhibin expression. This may be related to its content of safrole.
References
- ^ a b c GRCh38: Ensembl release 89: ENSG00000163083 – Ensembl, May 2017
- ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000037035 – Ensembl, May 2017
- ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ Burger HG, Igarashi M (April 1988). "Inhibin: definition and nomenclature, including related substances". Endocrinology. 122 (4): 1701–2. doi:10.1210/endo-122-4-1701. PMID 3345731.
- ^ a b "Entrez Gene: INHBB inhibin, beta B (activin AB beta polypeptide)".
- ^ Feng ZM, Bardin CW, Chen CL (June 1989). "Characterization and regulation of testicular inhibin beta-subunit mRNA". Mol. Endocrinol. 3 (6): 939–48. doi:10.1210/mend-3-6-939. PMID 2739657.
- ^ a b Krummen LA, Moore A, Woodruff TK, Covello R, Taylor R, Working P, Mather JP (April 1994). "Localization of inhibin and activin binding sites in the testis during development by in situ ligand binding". Biol. Reprod. 50 (4): 734–44. doi:10.1095/biolreprod50.4.734. PMID 8199254.
- ^ a b Ibrahim, A.A.E.M (2008). "Correlation between fennel-or anise-oil administration and damage to the testis of adult rats". Egyptian Journal of Biology. 10: 62–76.
- ^ Jin W, Arai KY, Herath CB, Kondo M, Ishi H, Tanioka Y, Watanabe G, Groome NP, Taya K (2001). "Inhibins in the male Göttingen miniature pig: Leydig cells are the predominant source of inhibin B". J. Androl. 22 (6): 953–60. PMID 11700859.
- ^ Lejeune H, Chuzel F, Sanchez P, Durand P, Mather JP, Saez JM (November 1997). "Stimulating effect of both human recombinant inhibin A and activin A on immature porcine Leydig cell functions in vitro". Endocrinology. 138 (11): 4783–91. doi:10.1210/en.138.11.4783. PMID 9348206.
- ^ Pierson TM, Wang Y, DeMayo FJ, Matzuk MM, Tsai SY, Omalley BW (July 2000). "Regulable expression of inhibin A in wild-type and inhibin alpha null mice". Mol. Endocrinol. 14 (7): 1075–85. doi:10.1210/me.14.7.1075. PMID 10894156.
- ^ Chong H, Pangas SA, Bernard DJ, Wang E, Gitch J, Chen W, Draper LB, Cox ET, Woodruff TK (July 2000). "Structure and expression of a membrane component of the inhibin receptor system". Endocrinology. 141 (7): 2600–7. doi:10.1210/en.141.7.2600. PMID 10875264.
- ^ Bernard DJ, Chapman SC, Woodruff TK (February 2002). "Inhibin binding protein (InhBP/p120), betaglycan, and the continuing search for the inhibin receptor". Mol. Endocrinol. 16 (2): 207–12. doi:10.1210/me.16.2.207. PMID 11818494.
Further reading
This article incorporates text from the United States National Library of Medicine, which is in the public domain.